Ozonation

Distribution by Scientific Domains
Distribution within Chemistry


Selected Abstracts


Ozonation of complex industrial park wastewater: effects on the change of wastewater characteristics

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 7 2009
Jen-Mao Fanchiang
Abstract BACKGROUND: Ozonation of complex industrial park wastewater was carried out in a semi-batch reactor. The variation of wastewater characteristics was evaluated based on the analysis of 5-day biochemical oxygen demand (BOD5) concentration, BOD5/chemical oxygen demand (COD) ratio, COD fractionation, and dissolved organic carbon (DOC) molecular size distribution before and after ozonation. RESULTS: The experimental results indicated that low efficiency of COD removal with increasing tendency of BOD5 concentration generally appeared after ozonation. Also, the BOD5/COD ratio increased from an initial of 0.27 to a maximum of 0.38. The COD fractionation tests revealed that most of the inert soluble COD was transformed to biodegradable soluble COD at 30 min of reaction time. Additionally, the DOC molecular size distribution tests showed that the fraction larger than 500 kDa was significantly decreased and the fraction smaller than 2 kDa was increased when the reaction time was prolonged to 240 min. CONCLUSION: This study verified that partial oxidation of the complex industrial park wastewater by ozonation could enhance wastewater biodegradability. The biodegradability enhancement was primarily because the inert soluble COD fraction was converted to the biodegradable soluble COD and the high molecular weight fraction of DOC was shifted toward the low molecular weight fraction. Copyright © 2009 Society of Chemical Industry [source]


Disinfection of recycled red-meat-processing wastewater by ozone

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 7 2005
Jiangning Wu
Abstract Ozonation of a real red-meat-processing wastewater was conducted in a semi-batch reactor to explore the possibility of the water reuse. The experimental results revealed that ozone was very effective in disinfection of the red-meat-processing wastewater. After 8 min of ozonation with an applied ozone dose of 23.09 mg min,1 liter,1 of wastewater, 99% of aerobic bacteria, total coliforms and Escherichiacoli were inactivated. Empirical models were developed to predict the microbial inactivation efficacy of ozone from the CT values for the real red-meat-processing wastewater. A correlation was also derived to estimate the CT values from the applied ozone dose and the ozone contact time. The results also revealed that under the ozonation condition for 99% inactivation of aerobic bacteria, total coliforms and E coli, the decrease in the chemical oxygen demand and the 5-day biological oxygen demand of the wastewater were 10.7% and 23.6%, respectively. However, ozonation under this condition neither improved the light transmission nor reduced the total suspended solids (TSS) despite of the decolorization of the wastewater after ozonation. Copyright © 2005 Society of Chemical Industry [source]


Ozonation of 1,3,6-naphthalenetrisulfonic acid in presence of heavy metals

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 8 2004
M Sánchez-Polo
Abstract A study was conducted of the mechanisms by which heavy metals, commonly present in industrial effluents, increase the purification effectiveness of ozone in the removal of organic contaminants of low biodegradability. For this purpose, the ozonation of 1,3,6-naphthalenetrisulfonic acid (NTS) in the presence of Ni(II), Fe(II), Mn(II), Zn(II), Sr(II), Cr(III), Cd(II), Hg(II), and Cu(II) was examined. The presence of small amounts of Mn(II), Fe(II), Ni(II), Zn(II), and Cr(III) was observed in the system, increasing the degradation rate of the NTS and transforming the dissolved organic matter into CO2. The mineralization of the organic matter was highly favored, especially in the first minutes of treatment. The results obtained appear to indicate that the activity of the metals in the NTS ozonation process is related to their reduction potential. Thus, metals susceptible to oxidation by ozone are potential promoters of NTS ozonation. The presence of Fe(II) or Mn(II) during NTS ozonation increased its degradation rate by 79% and 72% respectively. Moreover, the reaction kinetics of metal oxidation with ozone controls the increase in the purification effectiveness of these systems. The presence of radical scavengers (tert -butanol or bicarbonate) in the medium during the promoted ozonation of NTS showed a negative effect on this process, and the NTS degradation rate decreased with an increasing concentration of these inhibitors in the system. These results confirm that the degradation of NTS by ozone in the presence of heavy metals occurs by a radical mechanism. O3/Zn(II) and O3/Fe(II) systems were applied to the decontamination of urban waste waters. The presence of Zn(II) or Fe(II) during the ozonation produced a reduction during the first 5 min of treatment of 20% or 44%, respectively, in the concentration of dissolved organic matter present in the system. These results show that ozonation in the presence of heavy metals is a highly promising system for the purification of waste waters and industrial effluents. Copyright © 2004 Society of Chemical Industry [source]


Ozonation of vinasse in acid and alkaline media

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 11 2003
MA Martín Santos
Abstract The production of ethanol by fermentation and subsequent distillation generates wastewater known as ,vinasse'. This waste is highly polluting on account of its high organic load and antibacterial activity,which arises from the presence of phenolic compounds that reduce the efficiency of the detoxification treatments best suited to this type of waste (eg anaerobic digestion). This can be avoided by using a pre-treatment based on a chemical oxidant (ozone) at an acid or alkaline pH. Ozonation in acid media provides more selective elimination of phenolic compounds and a more readily biodegradable waste (ie an increased BOD5/COD ratio). Copyright © 2003 Society of Chemical Industry [source]


Removal of organic contaminants in paper pulp effluents by AOPs: an economic study

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 5 2002
Montserrat Pérez
Abstract The degradation of the organic content of a bleaching Kraft mill effluent was carried out using Advanced Oxidation Processes (AOPs). The study was focused on the identification of the AOP, or combination of AOPs, that showed the highest efficiency together with the lowest cost. Direct UV photolysis (UV), TiO2 assisted-photocatalysis (TiO2/UV), Fenton, Fenton-like, and photo-Fenton reactions (Fe(II)/H2O/UV), UV-assisted ozonation (O3/UV) and addition of Fe2+ and/or H2O2 to the TiO2/UV and the O3/UV systems, were used for the degradation of a conventional cellulose bleaching effluent. The effluent was characterized by the general parameters TOC, COD and color, and analyzed for chlorinated low molecular weight compounds using GC,MS. The costs of the systems per unit of TOC reduction were compared. Fenton, Fenton-like and photo-Fenton reactions achieved better levels of TOC degradation than photocatalysis and with lower cost's than photocatalytic treatments. Ozonation is an effective but rather expensive process. The use of UVA light, however, increased the effectiveness of ozonation with a significant decrease (>25%) in the operational cost. © 2002 Society of Chemical Industry [source]


Ozonation of activated sludge in the recycle stream

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 3 2001
A Huysmans
Abstract Intermittent ozonation of a part of the recycle sludge was performed two times a week for a laboratory-scale reactor at an average ozone dose of 0.019,g O3(gSSozonated),1. Under these conditions a decrease of about 50% in sludge growth was obtained for the ozone-treated system, in comparison with the control. As a consequence less sludge had to be removed from the test reactor. Only a slight decrease in quality of effluent was noticed. A comparative cost calculation was made, based on these results, between an ozone-treated activated sludge system and a traditional activated sludge system. © 2001 Society of Chemical Industry [source]


Efficacy and Safety Evaluation of Ozonation to Degrade Aflatoxin in Corn

JOURNAL OF FOOD SCIENCE, Issue 8 2002
A.D. Prudente Jr.
ABSTRACT: This study determined the efficacy and safety of ozonation in degrading aflatoxin in corn. Ozonation (10 to 12 wt%) reduced aflatoxin levels by 92% and no reversion to the parent compound was observed. Ozonation had minimal effect on fatty acids of uncontaminated corn, but had significant effect on fatty acids of contaminated corn. Crude extracts showed no mutagenic potential in the Ames assay using TA98 and TA100. Clean-up using hexane increased their mutagenic potentials. Clean-up using Mycosep columns increased the mutagenic potentials 18 to 617%. Hexane extracts from ozone-treated contaminated corn had lower inhibitory effect. This suggested that a fat-soluble mutagen is being formed or natural inhibitors of mutagenicity are being destroyed. [source]


Microbiological Benefits of Removing Foam Formed After UV-Enhanced Ozonation of Poultry-Processing Chiller Water for Recycling

JOURNAL OF FOOD SCIENCE, Issue 3 2002
M.E. Diaz
ABSTRACT: Prior experiments using 250 mL samples of unscreened poultry overflow chiller water evaluated the beneficial bactericidal and oxidative effects of 4 different treatments (namely, O2/O3,O2/UV, O2/O3/UV, and O2 as the control) for improving microbiological safety, turbidity, and water-use efficiency allowing its reconditioning for reuse. When excluding foam as in this present study, synergistic reductions > 1.5 log CFU/mL for aerobic plate counts (APC) were additionally achieved after 4 min for all O3/UV treatment combinations as compared to serially applied treatments of O3 and UV acting separately. With foam present, 16-min O3/UV treatments were required to achieve similar results. We now report these additional benefits achieved by removing the foam formed by the advanced oxidation process of ultraviolet-photon enhanced ozonation. Furthermore, foam microbial and general physical content were analyzed to determine suitability as an additive in rendering-type processes. Treatment of the wastewater resulted in total plate counts between 2 to 4 Log CFU/mL in the foam after 8 min. Fat and protein constituted 89% of the solids collected (384 mg/L or 14% of the foam) with trace amounts of metal elements (for example, Ca, Na, K, Fe, Cu) present. Irradiating had negligible effect on foam characteristics yet decreased the amount of solids collected. [source]


Oxygenation,Ozonation of Blood During Extracorporeal Circulation: In Vitro Efficiency of a New Gas Exchange Device

ARTIFICIAL ORGANS, Issue 9 2007
Velio Bocci
Abstract:, We have investigated the performance of a new gas exchange device (GED), named L001, specifically devised for the ozonation of human blood during extracorporeal circulation. This procedure, defined with the acronym "EBOO," means "extracorporeal blood oxygenation,ozonation." The innovative GED is made of microporous, ozone-resistant, polipropylene hollow fibers with an external diameter of 200 µm, a thickness of 50 µm, and a membrane surface area of 0.22 m2. The material is coated with phosphorylcholine on the external side in contact with the circulating blood, while a gas mixture, necessarily composed of medical oxygen and ozone (about 99 and 1%, respectively), flows inside the fibers in opposite direction. The new GED has been tested by using a buffered saline solution containing KI and by varying several parameters, and it has shown to be very versatile and efficient. Its main characteristics are minimal foreign surface contact, high gas transfer, and negligible priming volume. This device appears to be a practical, nontoxic, and rather inexpensive tool for performing ozonation of blood for already defined human diseases. [source]


Simultaneous afterclearing and decolorisation by ozonation after disperse dyeing of polyester

COLORATION TECHNOLOGY, Issue 4 2007
Hüseyin Aksel Eren
A set of trials have been conducted to examine the efficiency of ozonation on afterclearing of disperse dyed poly(ethylene terephthalate) fibres. Ozonation was performed in the cooled dyebath after the completion of the dyeing cycle. The ozone concentration used was 12.8 ± 0.3 mg/min at a gas flow rate of 400 ml/min. The results indicate that 3 min ozonation time is appropriate to achieve wash fastness results comparable to conventional reduction clearing. These results were obtained with simultaneous dyebath decolorisation ratios up to 67% and without significant colour yield (K/S value) losses of the dyed fabric. Ozonation periods exceeding 3 min caused significant colour yield (K/S value) losses, although dyebath decolorisation ratios increased up to 82% and wash fastness properties further improved. The chemical oxygen demand of the dyeing process decreased up to 62% by the ozonation afterclearing. The advantages of the ozonation afterclearing process are savings in terms of water, energy and time and reduction in environmental load. [source]


A performance comparison of individual and combined treatment modules for water recycling

ENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 4 2005
Stuart Khan
Abstract An Advanced Water Recycling Demonstration Plant (AWRDP) was commissioned and constructed by the Queensland State Government in Australia. The AWRDP was used to study the effectiveness of a variety of treatment processes in the upgrading of municipal wastewater for water recycling applications. The AWRDP consists of eight modules, each housing an individual specific treatment process. These processes are flocculation, dissolved air flotation, dual media filtration, ozonation, biological activated carbon adsorption, microfiltration, reverse osmosis, and ultraviolet disinfection. The individual performances of the treatment processes were determined, as well as their interdependence in series. A range of chemical water quality parameters were investigated. The study provides a broad process comparison on the basis of an important catalogue of these key parameters. This will be valuable in the selection and optimization of treatment processes trains in full-scale water recycling applications. © 2005 American Institute of Chemical Engineers Environ Prog, 2005 [source]


In-Situ ozonation of contaminated groundwater

ENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 3 2000
Michael A. Nimmer
This paper presents case studies in the application of insitu ozone sparging to remediate petroleum contaminated groundwater. This technology was developed and installed due to shortcomings with other conventional remedial technologies evaluated for groundwater remediation. The main objective of this study was to develop a system to supply ozone to the groundwater aquifer and to evaluate the system performance in the field. Three different applications were evaluated for this study, all containing petroleum-contaminated groundwater. The ozone sparging system consists of an air compressor, ozone generator, a programmable logic controller, and associated gauges and controls. The mixture of air and ozone is injected into the groundwater aquifer through microporous sparge points contained in various sparge well designs. The initial results from the three applications demonstrated that ozone sparging is a viable alternative to remediate petroleum -contaminated groundwater. Significant reductions in petroleum constituents we re observed shortly after system start-up at all sites. During the one to two years operation at the three sites, a number of maintenance items we re identified; these items we re addressed by modifications to the system design and operation. A long-term evaluation of the system operation has not yet been performed. [source]


Earthworm toxicity during chemical oxidation of diesel-contaminated sand

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 8 2005
Kyung-Hee Shin
Abstract An ecotoxicity test with Eisenia fetida was performed to monitor the removal of diesel and toxicity variation during the ozonation process. The three-dimensional (3-D) cell test was introduced for the monitoring of the ozonation process, and the removal rate based on total petroleum hydrocarbons (TPHs) mass was about 95% near the ozone inlet ports. This high removal rate might be caused by the low soil organic matter (SOM) content and low water content of sand. The use of a fiber-optic transflection dip probe (FOTDP) demonstrated that more than half of the injected ozone was consumed by reactions with diesel or natural ozone-consuming materials. The earthworm toxicity test using Eisenia fetida demonstrated that diesel concentrations in soil exceeding 10,000 mg/kg caused a dose-dependent weight loss in earthworms and increased mortality. Toxic effects were reduced greatly or eliminated after ozonation, and the degradation products of the ozonation were not toxic to the earthworms at the concentrations tested. One specific result was that the sublethal test on the earthworm might be more sensitive for the evaluation of the quality of contaminated soil, for some samples, which did not result in mortality and produced an adverse effect on weight. [source]


Effect of byproducts from the ozonation of pyrene: Biphenyl-2,2,,6,6,-tetracarbaldehyde and biphenyl-2,2,,6,6,-tetracarboxylic acid on gap junction intercellular communication and neutrophil function

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 3 2005
Stephanie L. Luster-Teasley
Abstract In this study, biphenyl-2,2,,6,6,-tetracarbaldehyde, an initial by product formed from the ozonation of pyrene, and biphenyl-2,2,,6,6,-tetracarboxylic acid, a subsequent pyrene ozonation byproduct, were evaluated using two toxicology assays to compare the toxicity of ozonation byproducts with that of the parent compound. The first assay measured the potential for the compounds to block gap junctional intercellular communication (GJIC) using the scrape loading/dye transfer technique in normal WB-344 rat liver epithelial cells. The second assay evaluated the ability of the compounds to affect neutrophil function by measuring the production of superoxide in a human cell line (HL-60). Pyrene significantly blocked intercellular communication (f= 0.2,0.5) at 40 ,M and complete inhibition of communication (f < 0.2) occurred at 50 ,M. Gap junctional intercellular communication in cells exposed to biphenyl-2,2,,6,6,-tetracarbaldehyde reached f < 0.5 at a concentration of 15 ,M. At concentrations greater than 20 ,M, biphenyl-2,2,,6,6,-tetracarbaldehyde was cytotoxic and the inhibition of GJIC was caused by cell death. Biphenyl-2,2,,6,6,-tetracarboxylic acid was neither cytotoxic nor inhibitory to GJIC at the concentrations tested (10,500 ,M). Exposure to biphenyl-2,2,,6,6,-tetracarbaldehyde resulted in a concentration-dependent decrease in phorbol 12-myristate 13-acetate,stimulated O12 production. Neither exposure to pyrene nor biphenyl-2,2,,6,6,-tetracarboxylic acid caused a significant toxic effect on neutrophil function. [source]


Wine waste treatment methodology

INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 10 2006
Ioannis S. Arvanitoyannis
Summary As more than 20% of wine production is waste, the latter constitutes a serious environmental problem that has to be solved urgently. Several methodologies such as composting, aerobic and anaerobic digestion, thermophilic anaerobic digestion, electrodialysis, pyrolysis, ozonation and wet oxidation among others were launched in an effort to solve effectively the wine waste management. This review aims at presenting comparatively and critically the characteristics of the currently employed waste treatment methods (properties, advantages and disadvantages, effectiveness) in order to emerge (with the aid of numerous tables and figures) the most promising and effective method. [source]


Diclofenac removal from water by ozone and photolytic TiO2 catalysed processes

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 6 2010
Juan F. García-Araya
Abstract BACKGROUND: The aim of this work was to establish the efficiency of single ozonation at different pH levels (5, 7 and 9) and with different TiO2 photolytic oxidizing systems (O2/UV-A/TiO2, O3/UV-A/TiO2 or UV-A/TiO2) for diclofenac removal from water, with especial emphasis on mineralization of the organic matter. RESULTS: In the case of single ozonation processes, results show fast and practically complete elimination of diclofenac, with little differences in removal rates that depend on pH and buffering conditions. In contrast, total organic carbon (TOC) removal rates are slow and mineralization degree reaches 50% at best. As far as photocatalytic processes are concerned, diclofenac is completely removed from the aqueous solutions at high rates. However, unlike single ozonation processes, TOC removal can reach 80%. CONCLUSION: In single ozonation processes, direct ozone reaction is mainly responsible for diclofenac elimination. Once diclofenac has disappeared, its by-products are removed by reaction with hydroxyl radicals formed in the ozone decomposition and also from the reaction of diclofenac with ozone. In the photocatalytic processes hydroxyl radicals are responsible oxidant species of diclofenac removal as well as by-products. Copyright © 2010 Society of Chemical Industry [source]


Ozonation of complex industrial park wastewater: effects on the change of wastewater characteristics

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 7 2009
Jen-Mao Fanchiang
Abstract BACKGROUND: Ozonation of complex industrial park wastewater was carried out in a semi-batch reactor. The variation of wastewater characteristics was evaluated based on the analysis of 5-day biochemical oxygen demand (BOD5) concentration, BOD5/chemical oxygen demand (COD) ratio, COD fractionation, and dissolved organic carbon (DOC) molecular size distribution before and after ozonation. RESULTS: The experimental results indicated that low efficiency of COD removal with increasing tendency of BOD5 concentration generally appeared after ozonation. Also, the BOD5/COD ratio increased from an initial of 0.27 to a maximum of 0.38. The COD fractionation tests revealed that most of the inert soluble COD was transformed to biodegradable soluble COD at 30 min of reaction time. Additionally, the DOC molecular size distribution tests showed that the fraction larger than 500 kDa was significantly decreased and the fraction smaller than 2 kDa was increased when the reaction time was prolonged to 240 min. CONCLUSION: This study verified that partial oxidation of the complex industrial park wastewater by ozonation could enhance wastewater biodegradability. The biodegradability enhancement was primarily because the inert soluble COD fraction was converted to the biodegradable soluble COD and the high molecular weight fraction of DOC was shifted toward the low molecular weight fraction. Copyright © 2009 Society of Chemical Industry [source]


Sequential anaerobic/aerobic biological treatment of olive mill wastewater and municipal wastewater

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 9 2006
Nikolaos Gizgis
Abstract This work investigated the efficiency of the combined anaerobic/aerobic biological co-treatment of olive mill wastewater and primary municipal wastewater. A laboratory-scale (6.5 L) upflow anaerobic sludge bed reactor received a mixture of olive mill wastewater and primary municipal wastewater at a loading rate ranging between 3 and 7 kg chemical oxygen demand (COD) m,3 day,1. The input COD concentration ranged between 1800 and 4400 mg L,1. The anaerobic reactor was operated at mesophilic conditions (35 °C). The effluent organic load was between 400 and 600 mg COD L,1, while the suspended solids removal efficiency varied between 75 and 95%. Average biogas production ranged between 3 and 4 L g,1 COD removed. The anaerobic reactor effluent was further treated in a laboratory-scale activated sludge treatment plant. Aerobic treatment reduced the organic load even further to 85,175 mg COD L,1. However, the final effluent still retained a significant level of colour. Removal of colour was possible by ozonation or coagulation. Finally, the treated effluent was non-ecotoxic, as indicated by the Daphnia magna toxicity test. This treatment method showed that it is feasible to treat olive mill wastewater in a municipal wastewater treatment plant by means of a high-rate anaerobic reactor located between the primary clarifier and the aeration tank. Copyright © 2006 Society of Chemical Industry [source]


Enhancement in mineralization of some natural refractory organic compounds by ozonation,aerobic biodegradation

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 2 2006
Devendra P Saroj
Abstract Two schemes, the first involving ozonation followed by final aerobic biodegradation (phase I experiments), and the second involving initial aerobic biodegradation, followed by ozonation and subsequent final aerobic biodegradation (phase II experiments), were examined for enhanced mineralization of refractory model compounds, viz. gallic acid, tannin and lignin. In all cases, and irrespective of the applied scheme, chemical oxygen demand (COD), total organic carbon (TOC), COD/TOC ratio, and specific UV absorbance at 280 nm attributed to the model compounds decreased with application of increasing ozone dose. The residual organic matter remaining after ozonation exhibited enhanced aerobic biodegradability in all cases. Further, in all cases and irrespective of the applied scheme, the overall amount of COD and TOC removed through the combination of ozonation and biodegradation processes increased with increase in ozone dose for all three model compounds, and more than 90% COD removal could be achieved with an ozone dose of 3 mg ozone absorbed per mg initial TOC, as compared with approximately 40% COD removal when no ozone was applied. Treatment by the first scheme resulted in the fraction of starting COD removed through biodegradation decreasing with increase in ozone dose in all cases, while this fraction increased or remained constant during treatment using the second scheme. In the case of tannin and lignin, similar overall COD removal could be achieved at lower ozone doses using scheme II. Due to incorporation of the initial aerobic biodegradation step in scheme II, the ozone requirement for additional mineralization, ie mineralization over and above that achieved by aerobic biodegradation, was also lower than that in scheme I. Copyright © 2005 Society of Chemical Industry [source]


Comparison between photocatalytic ozonation and other oxidation processes for the removal of phenols from water

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 9 2005
Fernando J Beltrán
Abstract Photocatalytic ozonation (1O3 + VUV + TiO2), ozonation (O3), catalytic ozonation (O3 + TiO2), ozone photolysis (O3 + VUV), photocatalysis (TiO2 + VUV) and photolysis (VUV) have been compared in terms of formation of intermediates, extent of, mineralization (TOC, COD, chloride, nitrate) and kinetics in the aqueous treatment of three phenols (phenol, p -chlorophenol and p -nitrophenol). In all cases, photocatalytic ozonation led to lower degradation times for chemical oxygen demand and total organic carbon removal. Intermediates formed were similar in the different oxidation systems with some exceptions. They can be classified into three different types: polyphenols (resorcinol, catechol, hydroquinone), unsaturated carboxylic acids (maleic and fumaric acids) and saturated carboxylic acids (glyoxylic, formic and oxalic acids). First order kinetic equations have been checked for the oxidation processes studied in the case of the parent compound. Rate constants of these systems have also been calculated. Copyright © 2005 Society of Chemical Industry [source]


Disinfection of recycled red-meat-processing wastewater by ozone

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 7 2005
Jiangning Wu
Abstract Ozonation of a real red-meat-processing wastewater was conducted in a semi-batch reactor to explore the possibility of the water reuse. The experimental results revealed that ozone was very effective in disinfection of the red-meat-processing wastewater. After 8 min of ozonation with an applied ozone dose of 23.09 mg min,1 liter,1 of wastewater, 99% of aerobic bacteria, total coliforms and Escherichiacoli were inactivated. Empirical models were developed to predict the microbial inactivation efficacy of ozone from the CT values for the real red-meat-processing wastewater. A correlation was also derived to estimate the CT values from the applied ozone dose and the ozone contact time. The results also revealed that under the ozonation condition for 99% inactivation of aerobic bacteria, total coliforms and E coli, the decrease in the chemical oxygen demand and the 5-day biological oxygen demand of the wastewater were 10.7% and 23.6%, respectively. However, ozonation under this condition neither improved the light transmission nor reduced the total suspended solids (TSS) despite of the decolorization of the wastewater after ozonation. Copyright © 2005 Society of Chemical Industry [source]


Ozonation of 1,3,6-naphthalenetrisulfonic acid in presence of heavy metals

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 8 2004
M Sánchez-Polo
Abstract A study was conducted of the mechanisms by which heavy metals, commonly present in industrial effluents, increase the purification effectiveness of ozone in the removal of organic contaminants of low biodegradability. For this purpose, the ozonation of 1,3,6-naphthalenetrisulfonic acid (NTS) in the presence of Ni(II), Fe(II), Mn(II), Zn(II), Sr(II), Cr(III), Cd(II), Hg(II), and Cu(II) was examined. The presence of small amounts of Mn(II), Fe(II), Ni(II), Zn(II), and Cr(III) was observed in the system, increasing the degradation rate of the NTS and transforming the dissolved organic matter into CO2. The mineralization of the organic matter was highly favored, especially in the first minutes of treatment. The results obtained appear to indicate that the activity of the metals in the NTS ozonation process is related to their reduction potential. Thus, metals susceptible to oxidation by ozone are potential promoters of NTS ozonation. The presence of Fe(II) or Mn(II) during NTS ozonation increased its degradation rate by 79% and 72% respectively. Moreover, the reaction kinetics of metal oxidation with ozone controls the increase in the purification effectiveness of these systems. The presence of radical scavengers (tert -butanol or bicarbonate) in the medium during the promoted ozonation of NTS showed a negative effect on this process, and the NTS degradation rate decreased with an increasing concentration of these inhibitors in the system. These results confirm that the degradation of NTS by ozone in the presence of heavy metals occurs by a radical mechanism. O3/Zn(II) and O3/Fe(II) systems were applied to the decontamination of urban waste waters. The presence of Zn(II) or Fe(II) during the ozonation produced a reduction during the first 5 min of treatment of 20% or 44%, respectively, in the concentration of dissolved organic matter present in the system. These results show that ozonation in the presence of heavy metals is a highly promising system for the purification of waste waters and industrial effluents. Copyright © 2004 Society of Chemical Industry [source]


Advanced oxidation processes for destruction of cyanide from thermoelectric power station waste waters

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 2 2004
José M Monteagudo
Abstract Several advanced oxidation processes for the destruction of cyanide contained in waste waters from thermoelectric power stations of combined-cycle were studied. Thus, oxidation processes involving ozonation at basic pH, ozone/hydrogen peroxide, ozone/ultraviolet radiation and ozone/hydrogen peroxide/ultraviolet radiation have been carried out in a semi-batch reactor. All these methods showed that total cyanide can be successfully degraded but with different reaction rates, and the decrease in the total cyanide concentration can be described by pseudo-first order kinetics. The influence of pH and initial concentration of hydrogen peroxide was studied to find the optimal conditions of the oxidation process. Experimental results of the single ozone treatment indicated that total cyanide is destroyed more rapidly at higher pH (12), while ozonation combined with H2O2 and/or UV is faster at pH 9.5. The optimum concentration of H2O2 was 20.58 × 10,2M because an excess of peroxide decreases the reaction rate, acting as a radical scavenger. The total cyanide degradation rate in the O3/H2O2(20.58 × 10,2M) treatment was the highest among all the combinations studied. However, COD reduction, in the processes using UV radiation such as O3/UV or O3/H2O2/UV was about 75%, while in the processes with H2O2 and/or O3/H2O2 was lower than 57% and was insignificant, when using ozone alone. Copyright © 2003 Society of Chemical Industry [source]


Mineralization improvement of phenol aqueous solutions through heterogeneous catalytic ozonation

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 12 2003
Fernando J Beltrán
Abstract To assess the mineralization level achieved, aqueous solutions of phenol have been treated with ozone in the presence of different solid catalysts. Activated carbon was the principal catalyst investigated, although some additional experiments were carried out by utilizing metal oxide-based catalysts (ie Ti, Co and Fe) supported onto alumina. Usage of Co/Al2O3 led to the highest values of phenol byproduct mineralization, nevertheless some metal leaching was experienced in the process. The operating variables studied when using activated carbon as the catalyst were ozone gas concentration, amount of catalyst added and temperature. Regardless of the catalyst type used, two different ozonation kinetic regimes were observed: (I) an initial period, corresponding to the presence of phenol in solution, characterized by small amounts of dissolved ozone and no improvement of the mineralization degree if comparing catalytic and non-catalytic runs; (II) a second period, free of phenol, in which dissolved ozone accumulated in water and the beneficial effects of catalysts on mineralization were noticed. Experimental data also demonstrated the improvement in oxalic acid elimination in the presence of heterogeneous catalysts. Finally, consumption of ozone per mass of carbon removed, reaction factors and Hatta numbers were also calculated. Copyright © 2003 Society of Chemical Industry [source]


Removal of organic contaminants in paper pulp effluents by AOPs: an economic study

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 5 2002
Montserrat Pérez
Abstract The degradation of the organic content of a bleaching Kraft mill effluent was carried out using Advanced Oxidation Processes (AOPs). The study was focused on the identification of the AOP, or combination of AOPs, that showed the highest efficiency together with the lowest cost. Direct UV photolysis (UV), TiO2 assisted-photocatalysis (TiO2/UV), Fenton, Fenton-like, and photo-Fenton reactions (Fe(II)/H2O/UV), UV-assisted ozonation (O3/UV) and addition of Fe2+ and/or H2O2 to the TiO2/UV and the O3/UV systems, were used for the degradation of a conventional cellulose bleaching effluent. The effluent was characterized by the general parameters TOC, COD and color, and analyzed for chlorinated low molecular weight compounds using GC,MS. The costs of the systems per unit of TOC reduction were compared. Fenton, Fenton-like and photo-Fenton reactions achieved better levels of TOC degradation than photocatalysis and with lower cost's than photocatalytic treatments. Ozonation is an effective but rather expensive process. The use of UVA light, however, increased the effectiveness of ozonation with a significant decrease (>25%) in the operational cost. © 2002 Society of Chemical Industry [source]


Use of various processes for pilot plant treatment of wastewater from a wood-processing factory

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 3 2001
Nikolaos S Athanasopoulos
Abstract The wastewater from a wood-processing factory is characterized by a high COD, chlorides and nitrogen content. Various treatment processes were applied to treat this wastewater in pilot-scale units. By applying one-stage denitrification,activated sludge biological treatment it was not possible to remove nitrogen. Nitrification was inhibited by wastewater compounds. By applying a second stage of a nitrification biofilter it was possible to have a high degree of nitrification. The denitrification was complete. With biological methods the reduction of COD, and -N and -N concentrations to acceptable values was not achievable. Physical,Chemical methods as H2O2/UV, electrolysis and ozonation were used as post-treatment of effluents from the biological system. Radical degradation, initiated by the powerful hydroxyl radicals which are generated from H2O2 by UV activation, is used for wastewater post-treatment. The combination of H2O2/UV was not suitable for post-treatment of this wastewater. With electrolysis, -N and COD removal can be complete. The total amount of ammonia and organic nitrogen converted to nitrate nitrogen for current density of 1.15,Adm,2 and energy consumption of 71.6,kWhm,3 was 0.35,gdm,3. Further biological denitrification is required for -N removal to permitted values. Energy consumption for the elimination of 1,kg COD was 40.4,kWh and 35.8,kWh for current densities of 0.7,Adm,2 and 1.15,Adm,2 respectively. The energy required to reach the limit value of COD equal to 150,mgdm,3 for current density of 1.15,Adm,2 was 71.6,kWhm,3. With ozonation, the COD removal can be complete. Further biological nitrification,denitrification is required to remove -N and -N to permitted values. At pH 7.0, in order to reach the limit value of COD equal to 150,mgdm,3, specific ozone dose was 6.0,g per g of COD removed and the total amount of ammonia and organic nitrogen converted to nitrate nitrogen was 0.25,gdm,3. The total equivalent energy required is estimated to be 75.0,kWhm,3. © 2001 Society of Chemical Industry [source]


Ozonation of activated sludge in the recycle stream

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 3 2001
A Huysmans
Abstract Intermittent ozonation of a part of the recycle sludge was performed two times a week for a laboratory-scale reactor at an average ozone dose of 0.019,g O3(gSSozonated),1. Under these conditions a decrease of about 50% in sludge growth was obtained for the ozone-treated system, in comparison with the control. As a consequence less sludge had to be removed from the test reactor. Only a slight decrease in quality of effluent was noticed. A comparative cost calculation was made, based on these results, between an ozone-treated activated sludge system and a traditional activated sludge system. © 2001 Society of Chemical Industry [source]


Efficacy and Safety Evaluation of Ozonation to Degrade Aflatoxin in Corn

JOURNAL OF FOOD SCIENCE, Issue 8 2002
A.D. Prudente Jr.
ABSTRACT: This study determined the efficacy and safety of ozonation in degrading aflatoxin in corn. Ozonation (10 to 12 wt%) reduced aflatoxin levels by 92% and no reversion to the parent compound was observed. Ozonation had minimal effect on fatty acids of uncontaminated corn, but had significant effect on fatty acids of contaminated corn. Crude extracts showed no mutagenic potential in the Ames assay using TA98 and TA100. Clean-up using hexane increased their mutagenic potentials. Clean-up using Mycosep columns increased the mutagenic potentials 18 to 617%. Hexane extracts from ozone-treated contaminated corn had lower inhibitory effect. This suggested that a fat-soluble mutagen is being formed or natural inhibitors of mutagenicity are being destroyed. [source]


Microbiological Benefits of Removing Foam Formed After UV-Enhanced Ozonation of Poultry-Processing Chiller Water for Recycling

JOURNAL OF FOOD SCIENCE, Issue 3 2002
M.E. Diaz
ABSTRACT: Prior experiments using 250 mL samples of unscreened poultry overflow chiller water evaluated the beneficial bactericidal and oxidative effects of 4 different treatments (namely, O2/O3,O2/UV, O2/O3/UV, and O2 as the control) for improving microbiological safety, turbidity, and water-use efficiency allowing its reconditioning for reuse. When excluding foam as in this present study, synergistic reductions > 1.5 log CFU/mL for aerobic plate counts (APC) were additionally achieved after 4 min for all O3/UV treatment combinations as compared to serially applied treatments of O3 and UV acting separately. With foam present, 16-min O3/UV treatments were required to achieve similar results. We now report these additional benefits achieved by removing the foam formed by the advanced oxidation process of ultraviolet-photon enhanced ozonation. Furthermore, foam microbial and general physical content were analyzed to determine suitability as an additive in rendering-type processes. Treatment of the wastewater resulted in total plate counts between 2 to 4 Log CFU/mL in the foam after 8 min. Fat and protein constituted 89% of the solids collected (384 mg/L or 14% of the foam) with trace amounts of metal elements (for example, Ca, Na, K, Fe, Cu) present. Irradiating had negligible effect on foam characteristics yet decreased the amount of solids collected. [source]


Inactivation of Salmonella enterica serovar enteritidis in shell eggs by sequential application of heat and ozone

LETTERS IN APPLIED MICROBIOLOGY, Issue 6 2008
J.J. Perry
Abstract Aims:, To assess the contribution of ozone to lethality of Salmonella enterica serovar Enteritidis in experimentally inoculated whole shell eggs that are sequentially treated with heat and gaseous ozone in pilot-scale equipment. Methods and Results:, Whole shell eggs were inoculated with small populations of Salmonella Enteritidis (8·5 × 104,2·4 × 105 CFU per egg) near the egg vitelline membrane. Eggs were subjected to immersion heating (57°C for 21 min), ozone treatment (vacuum at 67·5 kPa, followed by ozonation at a maximum concentration of approx. 140 g ozone m,3 and 184,198 kPa for 40 min) or a combination of both treatments. Survivors were detected after an enrichment process or enumerated using modified most probable number technique. Ozone, heat and combination treatments inactivated 0·11, 3·1 and 4·2 log Salmonella Enteritidis per egg, respectively. Conclusions:, Sequential application of heat and gaseous ozone was significantly more effective than either heat or ozone alone. The demonstrated synergy between these treatment steps should produce safer shell eggs than the heat treatment alone. Significance and Impact of the Study:, Shell eggs are the most common vehicle for human infection by Salmonella Enteritidis. Many cases of egg-related salmonellosis are reported annually despite efforts to reduce contamination, including thermal pasteurization of shell eggs and egg products. Treatment with ozone-based combination should produce shell eggs safer than those treated with heat alone. [source]